Bacterial motility, and in particular repulsion or attraction toward specific chemicals, has been a subject of investigation for over 100 years, resulting in detailed understanding of bacterial chemotaxis and the corresponding sensory network in many bacterial species. For Escherichia coli most of the current understanding comes from the experiments with low levels of chemotactically active lig...

We tested time perception in a bisection task featuring a wide range of durations (from 0.2 to about 8.0s) and highly arousing stimuli (delivery of an electric shock). In addition, self-report questionnaire responses and skin conductance responses were assessed to measure emotional reactivity. Results clearly demonstrated emotion-related time distortion, as stimulus durations were judged to be ...

We compared aspects of the thermal sensitivity of replicated lines of Drosophila melanogaster that had been evolving by laboratory natural selection at three selection temperatures: 16.5 degrees C (10+ yr), 25 degrees C (9+ yr), or 29 degrees C (4+ yr). The 16.5 degrees C and 25 degrees C lines are known to have diverged in fitness at 16.5 degrees C versus 25 degrees C and also in heat toleranc...

transient compressive excitation is described and tested. It is shown that impacts induce a chaotic collapse of crumple layers. The simulations predict shock pulses and intralaminar forces. Simulated shock pulses that a free-falling mass is subjected to, and the corresponding animated deformation histories of the layers, are compared with the high-speed videography. Cushioning performance maps ...

Classical dynamic fracture theories predict the surface wave speed to be the limiting speed for propagation of in-plane cracks in homogeneous, linear elastic materials subjected to remote loading. This report presents experimental evidence to the contrary. Intersonic shear-dominated crack growth featuring shear shock waves was observed along weak planes in a brittle polyester resin under far-fi...

Direct real-time visualization and measurement of laser-driven shock generation, propagation, and 2D focusing in a sample are demonstrated. A substantial increase of the pressure at the convergence of the cylindrical acoustic shock front is observed experimentally and simulated numerically. Single-shot acquisitions using a streak camera reveal that at the convergence of the shock wave in water ...

Observations from Magnetospheric MultiScale (~8 Re) and Van Allen Probes (~5 and 4 Re) show that the initial dayside response to a small interplanetary shock is a double-peaked dawnward electric field, which is distinctly different from the usual bipolar (dawnward and then duskward) signature reported for large shocks. The associated E × B flow is radially inward. The shock compressed the magne...

Voyager 2 (V2) has observed heliosheath plasma since 2007 August. The plasma flux decreases by 25% before the termination shock (TS), then, as V2 moved into the heliosheath, the plasma density, temperature, and flux all decreased by an additional factor of 2. We suggest three effects combine to cause these decreases. (1) V2 moved into the lower-flux transition region between the lowand high-spe...

The approximation of shock waves by nite diierence schemes is considered. This question has been investigated by many authors, but mainly under some restrictions on discrete wave speeds. Basic works are due to Majda and Ralston (rational speed) and, more recently, to Liu and Yu (Diophantine speed). The main purpose of the present work is to obtain shock prooles of arbitrary speed for rather gen...